Stoker drive mechanism



vJune 18, 1935. H. E. PRESTON STOKER DRIVE MECHANISM Filed Sep.. 1'7, 1950 9 Sheets-Sheet l Xml June 18, 41935. H. E. PRESTON STOKER DRIVE MECHANISM Filed sept. '17', 1930 9 Sheets-Sheet 2 June 18, 1935. H. E. PRESTON 2,005,005

sToKER DRXVE MECHANISM Filed Sept. 17, 1950 9 Sheets-Sheet 3 June 18, 1935. E. PRESTON 2,005,005

STOKER DRIVE MECHANISM Filed Sepi. l', 1950 9 Sheets-Sheet 4 ,June 18, 1935. H. EPRESTON STOKER DRIVE MECHANISM 9 sheets-sheet 5 Filed Sept. 17, 1930 June 18, 1935. H. E. PRESTON I 2,005,005

STOKER DRIVE MECHANI SM Filed Sep'. 17, 1930 9 Sheets-Sheet 6 WNV mam-5 Jun 18, 1935. E PRESTON l 2,005,005

sToKER DRivE MECHANISM Filed Sept. 17, 1950 9 Sheets-Sheet '7 I June 18, 1935. EY PRESTON n 2,005,005`

STOKER DRIVE MECHANI SM Filed Sept. 17, 1930 9 Sheets-Sheet 8 fwefdfor. @MME/QQ@ H. E. PRESTON 2,005,005

STOKER DRIVE MECHANISM Filed sept. 17, 1930 9 Sheets-sheet 9 `June 18, 1935.

Patented June 18, 1935 e s'roKER naive MEoHANrsM HerbertE. Preston, Philadelphia, Pa., assgnor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania y Application September 17, 1930, Serial No. 482,617

6 Claims.

A principal object of this invention is to pro` vide a mechanical stoker having generally improved fuel-feeding mechanism.

Another object is to provide improved drive means for the fuel-feedingelements of an underfeed Stoker affording a maximum flexibility of adjustment and a consequent superior control of the feeding operation.

Still another object is to provide an improved Stoker drive wherein the primary and secondary elements are so disassoeiated as to prevent undesirable reactions adversely affecting the efliciency and durability of the mechanism.

A further object of the invention is to provide a drive connection between the prime mover yand the primary fuel-feed ram which substantially eliminates transverse components andrestricts the thrust upon the ram to a straight line corresponding to the axis of the cylinder in which the ram operates. v

A still further and specific object of the invention is to'provide an improved and simplified drive for the fuel-feeding elements of 'an' underfeed vStoker affording independent adjustment of the individual elements. y n

Another object is to provide an adjustable drive of the stated character in which the adjustments maybe made from the exterior of the stoker structure. y

Still another object of the invention is to provide a transmission mechanism for the rams and pushers of a stoker mechanism which shall be characterized by the inclusion of one or moreV safety devices preventing damagefto the parts, as hereinafter set forth.

The invention further resides in certain novel' mechanical and structural features hereinafter set forth and illustrated in the attached drawings, in which:

Figure l is a more or less diagrammatic vertical sectional view through a mechanical Stoker of the underfeed type illustrating an embodiment of my invention.; y f

Figs. 2 and 3 are fragmentary elevational views illustrating details of the mechanism and showing certain of the operating parts in alternative posi-4 tions;

Fig. 4 is a front elevational View of a portion of the mechanism forming a part of the present invention;

Fig. 5 is a plan view of that portion of the mechanism illustrated Kin Fig. 4;

Fig. 6 is a sectional View on the line 6-6,`

Fig. 2; f p

Figs. 7 and 8 are fragmentaryenlarged sectional views illustrating details of the mechanism;

Fig. 9 is a fragmentary sectional view illustrating a modification withinthe scope of the invention; f Fig. 1D is the front View of the mechanism shown in Fig. 9; v

Fig. l1 is a sectional elevational View illustrating a further embodiment 'of the invention; and y Figs. 12, 13 and 14 are side elevational-views:- illustrating still kother modificationsl within the scope of the invention.

With reference to the drawings, I indicates the n front wall of a furnace equipped with an underfeed Stoker of well known type. This stoker comprises an inclined grate made up of `alternating retorts, 2, and tuyre sections, 3, said retorts com-` in accordance with the well known principles of operation ofA this type of apparatus. y At the bot tom, the grate structure, as outlined above, in'- cludes an extension grate 5 which also is adapted to be reciprocated in well known manner. The grate terminates in an ash pit 6 and beneath the inclined `grate structure is a space 9 into'which combustion air is forced from suitable blower apparatus' (not shown), and from which the lair passes through the tuyres 3 to the fuel bed. Q

Fuel is fed to the upper ends of the retorts from hoppers I I through the medium of main fuel rams I2, see Figures 2 and 3, which operate in cylinders- I3 with which the'hoppers I I communicate. f Byt into'the upper ends of the retorts 2 in which thefuel is advanced by the secondary pusl'iers` 4 ata predetermined rate towards the bottom of thev grate structure. During this movement, the fuel is consumed until at the bottom the remnants andk ashes are passed'to and over the extensiongrate into the ash pit 6'.

The actuating means for the ram I2 andpushers 4 may consist of any suitable form of motor (not. shown) which in the present instance is con` nected through'power gearing I4 toa main crank shaft I5 journaled at the front of the stoker out- Wardly of the ram cylinders,l as illustrated. Each Y of the ram cylinders I3 has connected to the outer end thereof a bracketv I6, in the upper part of" f which the crank shaft I5 is journaled, seefFigs. '2l 54 to 5, inclusive. In the embodiment of my invention illustrated in Figs.k 1 to 6, each of these brackets also comprises bearings II in which is journaled a bell crank lever I8, one arm of which is connected through a rod I9 with a crank arm of the shaft I5. Preferably, the rod I9 is connected to the bell crank through the medium of a pin 2| which is adapted to shear under a predetermined strain, this pin thereby constituting a safety feature, as hereinafter set forth in greater detail;-- The pin-2| preferably is mounted in steel bushings 22 forming a part of the connecting rod and of the bifurcated arm 23 of the bell crank,l

between which bifurcations the connecting rod is secured. l

Another arm 24 of the bellcrank lever is connected through a link 25 to the raml I2, the axis of the pivotal connection 26 between the ram and the said link preferably extending -through or ad` jacentto the center of massof the said ram.A Forl this purpose, the ram is made hollow at its rearwardendthe =linkvextending into the hollow interiorasillustrated.v v It will be noted that the arc described bythe outerend of the arm 24 and by the pin 28 which connects the link 25 to the ybell crankcorresponds closely to the extension of the longitudinal axis of the ram I2 and; ofV the cylinder I3 in .which the ram operates. The deviation fromthis, axis of theline of movement of the pin 28 is so slight as to afford what in effectis a straight linethrust between the bell crank and the rainy-I2, substantially devoid of transverse components, whereby wearl between the ram and the ramcylinder due to such component thrusts is'reduced toa minimum.

The .bell crank I8 also comprises a depending arm3l, the bifurcations 32 of which, see Fig. 4, are `spacedto ,admit blocks 33, 33 having trunnions 34 ,journaled in bearings inthe bell crank bifurcations., The blocks .33 are apertured for reception ofpuslirodsr 35, eachof the blocks having in the p resentinstancethree such apertures through whichv extend a corresponding numberof the rods.

, The rods 13,5.are individually connected through swivelnconnections 36 witha corresponding number; of rods31 each slidably supported and guided ill-fthe ,fro1 it.wall I of the stoker, means being providedin. the. .form of packing boxes 38 for sealing, the joints between the rods and the wall. The rod`sl3f|fare in turn individually connected, each through a connecting rod y39 and a pivoted lever 4I,`to the secondaryrams 4, of which in the presentinstancethere are ve, and to the exten- .siongrate .5. Thus eachof the secondaryrams 4 and extensiongrate 5 hasy an individual conmention-through .the rods-withnthe bell-crank I 8.

It will, be noted'by reference to Figs. 2 to 5, inclusiva-that the vouter Vends ofy the rods 35 projectbeyondthe blocks 33 to provide for receptionpf a plurality of horseshoe washers 51 which inthe. illustrated instance are confined betweenacollar. 58 at the outer-endpof each of the rods and a Washer59-which abuts the forward.rivexed` faceof the trunnion block 33. The` opposite similarly convexed face of the trunnion block is engaged in each instance by a col` lar lil), which is suitably, connected, as for examplebyla shear pin 10,'to itsv respective rods.- The horseshoe, washers 51 being detachable `constitute a means 'for regulatingthe amount of lost motion between` the.v arm 3I of the bell crank and the rods35,handvals o for .adjusting to some extent the.positionl of vthe pathof travel of the secondary ,within their` individual guides. Preferably', the.v collars` 58 are secured. to theirl respective rods 1 by., rneans, of pins., 6 I :,which,4 vlike the -pins` 'I0 are adapted to shear under a predetermined strain to thereby afford a factor of safety in the event that undue strains are placed upon the mechanism. It will be noted that the apertures in the blocks 33 through which the rods extend are flared toward each end, this with the convexed face formation, which gives line contact between the block and the washer 59 and collar 60, providing for free self-adjustment between the blocks and rods for the changing relativeangular positions. l

-Further adjustments of ther secondary rams andofwtheextension grate with respect to the actuating mechanism and to each other may be had when desired by means of an adjustable connection between the levers 4I and the rams or grate such as illustrated at 5I in Fig. 1 and in Fig. 8. lAs shown in Fig. 7, each of the pushers 4 has a depending lug 62 apertured at 63 for reception of a. rod 65 constituting a pivoted end portion of the associated lever 4l. Each of the rods 65 carriesa washer 66 which abuts a shoulder at the inner end ofthe rod and engages a spherical projection 61 on one face of the lug 62, Whileva second washer 6B, confined to the rodby a collar 69 on the outer end thereof, enn gages a correspondingA projection on the opposite face of the lug. By reason-of the flared formationof the ends of they apertures 63 .and the spherical projections 6l, the rods 65 are freely adjustable in the lugsas required by the changing angularities of thelevers 4I. In theadjustable connection 5I, referred toabove, see Fig. 8, the rod, 65a, is elongated and is slidably supported in a trunnion block 'II pivotally supported in the bifurcated end of the lever 4I. length of the rod provides for application thereto of horseshoe or other suitable washers l2:

The rod carries at its extremities, secured there-- to preferably by shear pins 'I3 and 14, collars 15 which conne the block 1I and the washers 'l2 and, between these elements, the lug 62of :the pusher. Washers 'I6 are provided for engagement with the opposite faces of the said lugs.` Byk varying the position of the lug longitudinallyjof the rod, as determined by the disposal of washers, the position. of the path of travelk of the pusher in itsguides may be varied; and byre-y Vmoving a number of the Washers the extentof varied as re- The extra ment, in effect, provides independent driving connections for the, primary and secondary rams and eliminates the undesirable and destructive inter-reaction thrusts. This in conjunctionwith the substantialV elimination of transverse components in the operation of the main rams, as previously set forth, reduces wear4 in the vrains and their `cylinders to a minimum and lalfords' a mechanism of great durability. A close fit". be-1V tween the' rams and their cylinders is continuously maintained and sifting of fuel between-` these partsis largelyv prevented. y

AttentionY is directed -to the applicants use of a plurality ofshearpins which afford a substantially complete protection for the mechanism in event of the jamming of any of the moving parts. The pin 2| connecting the main connecting rod I9 to thebell crank'ai'fords protectionto the power gearing I4 Iin the event of obstruction interfering with the movement of either the main feed ram or of the Vsecondary pushers, the location ofthe pins -2I betweenthe connecting rod and the bell cranks being a particularly desirable one where, asfrequently occurs, several` of the-primary rams ofthe stoker are driven from a single power box. Inadditionto the pin 2|, each of the connections between the bell'crank'and Athe rods extending to the secondary pushers is protected throughthe shear pins 6I and 10, and still further protectionis afforded inthe use of the shear pins -13 `and 'I4 in the connection between the. pushersY and the various pusher-actuating levers. y y

There may, of course, be many modifications without departurefrom theinvention. In Figs. Sland^ l0, for example,`I have illustrated a composite leverthat may be usedito replace the bellcrank I8. f This Alever consists-of two bell-cranks `IllllandfII'II which are keyed to a shaft |02, the

latter in assembly being journaled inthe bearings;|`|. In this instance the rod I9 is connected by a pin |03 to one arm` of each of the levers |00 and IDI, while the other arms may be connected to the link 25. Also keyed to the shaft I2 are three arms |04, to each of which, in the present instance are pivotally connected two rods |05 .z which correspond to the rods 35 of the previously described embodiment and which extend to the pushers as previously set forth.

. In Fig. 1l is illustrated another embodiment of my invention in which the bell crank I8 is re'- placed by ra simple lever |06 the upper end of which `is connected through rods III'I and |08 to the main 'ram I2 and to thecrank shaftl I5 respectively. The lowerend of this lever may be bifurcated for connection therewith'throughthe medium of pins |09 of the required number of pusher rodsA I I I, which in turn are connected as previously set forth to the secondary rams.

In the embodiment shown in Fig. 12, the bell crank lever I8 is retained but instead of connecting the entire set of secondary ram rods directly thereto, certain of these rods are co-nnected to a simple lever IIZ which is connected through a link I I3 to the lower arm of the bell crank. This .system might be extended by the addition of still other levers for additional rods or for a more favorable distribution of the rods originally employed.

In Fig. 13, I have illustrated the application of the aforedescribed bell crank drive to pusheroperating mechanism of the type disclosed in my copending application, Serial Number 425.316, led Feb. 1, 1930. In this instance, the pushers (not shown) are connected with rods 'I'I each of which, like those shown, is slidably mounted in suitable guides 'i8 on the fixed frame of the stoker mechanism. The rods extend outwardly at the front of the Stoker through outer guides I9 and have fixed to their ends collars 8| and at a point inwardly of said end, a second collar 82. A cross head 83 surrounds each of the rods I'I and is adapted for reciprocation inv the outer guide 19, and provision is made for applying to the rods a plurality of removable washers 84 by means of which the lost motion between the cross head and the rod may be regulated as required. The cross 3 headis connected'I through alinkS-'with a-bell crank 86 pivotally connected at-8`I to the xed structure of the Stoker and having its other end connected with arod `8 8 which through a -link 89, a second bell crank lever 9| and a connecting ,Y

rodf92 is connected tothe lower depending arm Sib of the main bell crank.Y Movement of the bell crank Illa asidescribed above is'transmitted `through the rod 92, bell crank 9| 'and link 89 to the-rod 88,v and thence through the bell cranks S6 and links 85 to the cross heads 83. Reciprocation of the cross heads results in a movement Y of the rods 'I1 and of the pusher connected therewith. f v f `While the use of a suitable lever interposed` between the main and secondary rams constitutes a. desirable embodiment of my invention, as set forth above, there may be other embodiments such forV example, as that shown in Fig. 14.' In

this rinstance I employ an auxiliary crank shaft H4 to which the secondary ram rods |I5 are connected through the medium of a lever IIG and a connecting rod I'I, the main ram I2 being connected through rods. I I8 and IIS to the 'main` crank .shaft I 5. In the present instancethe auxiliary crank shaft is connected to the main shaft and to the prime mover by gearing I2 I-I22, this simplifying synchronization of the ram actions, although separate power sources may be employed for the two shafts without departure from thev invention. In this instance, also, a crosshead I23is usedbetween the rods I|8 and |I9,`

this crosshead reciprocating in guides |24fand insuring an absolutely straight line thrust upon the main ram free from transverse components. It will be noted thatthisembodiment.retains all the advantagesof those previously described.

There may be further modication without departure from the invention. f Y

l. In a stoker, the combination with a retort including a plurality of fuel feeding elements, of a ram for feeding fuel into said retort, a front wall, a lever mounted outwardly of said wall, a link connecting said lever to said ram at a point substantially along the longitudinal center line of the latter, said parts being so disposed that 4upon oscillation of said lever a substantially straight line motion is imparted to said ram, an actuating rod for each of said fuel feeding elements,

`said rods extending through bearings provided in said front wall, a second rod pivotally connected tothe outer end of each of said first mentioned rods, a member pivotally mounted in said lever on an axis transversely to the plane in which the lever oscillates, apertures provided in said member through which said last mentioned rods eX- tend, means for preventing displacement of Said rods `from said apertures, and means for actuating said lever.

2. In a stoker, the combination with a retort including a plurality of fuel feeding elements, of a ram for feeding fuel into said retort, a front Wall, a lever mounted outwardly of said wall, means pivotally connecting the said lever to said ram at a point substantially along the longitudinal center line of the latter, kwhereby upon oscillation of said lever a substantially straight line motion is imparted to said ram, an actuating rod for each of said fuel feeding elements, said rods extending throughbearings provided in said front wall, a second rod pivotally connected to the outer end of each of said rst mentioned rods, a member pivotally mounted in said lever on an axis transversely to the plane in which the lever oscillates,

apertures provided in saidmember through which said last mentioned rods extend,lmeans for preventing displacement ofsaid rods from said apertures, and means forv actuating saidlevers.l

3. In a, Stoker, the combination with a retort including a plurality wof fuel feedingvelements, of a ram for feeding fuel into said retort,y a front wall, a leverl mounted outwardly of said wall, av link connecting said lever to said ram ata point substantiallyalong the center line of the latter, said parts being so disposed that upon oscillation of said lever a substantially straight line motion is vimparted to said ram, an actuating ,rod for eachof said fuel feeding elements, said rods extending through bearings provided in said front Wall, a second rod pivotally connected to the outer end of each of said first mentioned rods, a member pivotally mounted Vin said lever on an axis transversely to the plane in which the lever oscillates, apertures provided in said member through which said last mentioned rods extend, collars mounted on each of said last mentioned rods preventing displacement of the latter from said aperytureasaid collars being spaced apart to permit lost motion between said rods and said member, and a plurality of washers adapted to be detachablymounted on said rods intermediate the collars to thereby regulate the extent of said lost motion, and means for actuating said lever.

4. In a Stoker, the combination with a retort including a plurality of fuel feeding elements, of

va ram `for feedingfuel into said retort, a cylinder for said ram, a pivoted lever, means extending into one end of said kcylinder only, and connecting said lever to said ram at a point substantially along the longitudinal center line of the latter, whereby upon oscillation `of said lever a substantially straight line vmotion is imparted to said ram, rods constituting connecting links between said lever and said fuel feeding elements and mounted for longitudinal reciprocation by oscillation of said lever, a member pivotally mounted in said lever on an axis transversely to the plane in which the lever oscillates, said member being apertured transversely to the pivotal axis thereof and said rods passing loosely through saidapertures, means .for preventing displacement of the rods from'the apertureag andmeans for actuating said lever, s v

5.` In a Stoker, the combination-with aretort including a. plurality of fuel-feedinglelements, of v a ram for feeding fuel into said retort,fa front Wall, -a lever mountedV outwardly 4'of said wall, means connecting said lever to -said ram-ata point substantially along kthe longitudinal center line ofthe latter, whereby upon oscillation of said lever a substantially straight linefmotion is im parted tosaidram, rods constituting connecting linksbetween the lever and saidfuelf'feedingelements, said rods extending through'bearings. provided iny said front wall, a member pivotally mounted insaidlever on anaxis `transverselyto the plane in which saidlever oscillates, said mem'- ber being aperturedtransverselyvto"the pivotal axis thereof, and said rods passing loosely through said aperturesgmeans for preventing: displaceH ment of said rods from said apertures, and'means for actuating said lever. i

6. In a Stoker, the combination with a retort including a plurality of fuel feeding elements,'.of

`a ram for feeding fuel into said retort, a cylinder for said ram,` a pivoted lever, means comprising one or more links-extending into one end ofusaid cylinder only, and connecting saidilever f to .saidram at a point substantially along thev longitudi.. nal center line of the latter, whereby oscillation of said lever imparts a substantially straight line motion to said ram, rods connecting said lever to said fuel feeding elements, a member pivotally mounted in said lever on an axis transverselyto the plane inwhich said lever oscillates, said member being aperturedl transversely"tothepivotal axis thereof, and said rodsv passing `loosely' through said apertures, collars mounted on each of said rods for `preventing displacement of the rods from the apertures-said collars being spaced apart to permit lost'motion between the rods and the apertured member, a plurality of 'washers detachably mounted on said rods intermediate the collars to thereby regulate lthe extent of said lost motion, and means for actuating said lever.

HERBERT E. PRESTON 

